reactor_running? will be true just after the thread enters
EventMachine.run; reactor_thread only gets set after the internal
initialize_event_machine method has been called, the C extension is set
up, and it is entering its run loop.

Make sure the file doesn't exist until we've finished writing it.

removed `@current` as it is not used

fix typo in changelog

Fix typo in Rails 5.0 release notes – “when when”

[ci skip]

Explicitly document 'false' as value for 'action_on_unpermitted_parameters'

[ci skip]

Prior to this commit, `3.months - 3.months` would result in a duration
that has the "parts" of `[[:months, 3], [:months, -3]]`. This would mean
that it was subtly different than `2.months - 2.months`. When applied to
a time, the date might actually change if the resulting day doesn't
exist however many months in the future, even though in both cases we
just wanted to add `0`, which should always be an identity operation.

With this change, we now store the parts as a hash, so `3.months -
3.months` is simply stored as `{ months: 0 }`.

Fix that unsigned with zerofill is treated as signed

Add Yarn support in new apps using --yarn option

Add note about step needed to get tests to pass if you implemented basic auth [ci skip]

Add rubocop to Gemfile

use public Module#include instead of send :include

I found this issue and wanted to give the fix.

fixing update_all and delete_all when chained with left_joins

Mention the Accept header and how that figures into the request format.

Wrongly added when fixing the request path wrangling.

Fixes #27125.

Follow up to #18767

Merge pull request #26865 from sergey-alekseev/uniqueness-validation-scope-with-polymorphic-association

fix the uniqueness validation scope with a polymorphic association

If it's enabled globally, it's on regardless of how individual threads
are set.